This invention relates to a device used to diagnose the focuses of cancer, and particularly to a device for irradiating a cancer with a laser beam where a photosensitive material such as hematoporphyrin derivatives having an affinity to cancer and other tumors has beforehand been absorbed by the cancer.
Continuous krypron laser beams have been used for a diagnosis of cancer, and continuous argon laser beams have been used for a treatment of the focuses of cancer. Devices used for these purposes have been proposed (Japanese Utility Model Application No. 159142/1981 filed by Yoshihiro Hayata, Katsuo Aizawa and Harubumi Kato).
FIG. 1 shows the schematic diagram of the device according to the above-mentioned Japanese Utility Model application. In the device shown, hematoporphyrin derivative is beforehand absorbed in both focus A of the cancer and its peripheries B before the start of a diagnosis of the cancer. Endoscope 1 faces the focus A and its peripheries B.
Visible rays from krypton laser beam source 5 are selectively transmitted through mirror 7 to light pipe 12, and they are incident upon focus A and its peripheries B. An image of focus A and its peripheries B is picked up by use of image guide 11, and then it is fed to image intensifier 3 through bandpass (color) filter 2 in order to observe the image.
For the treatment of the affected part of flesh, visible rays from argon dye laser source 6 are transmitted through light pipe 12 thereto.
This device permits the diagnosis and treatment to be carried out in a new mode. However, it is difficult for the focuses of cancer in the early phase to be detected. The reason is as described below.
When a hematoporphyrin derivative has been absorbed in focus A of cancer and its peripheries B, fluorescence occurs in these locations peaking at both 630 nm and 690 nm. The magnitude of fluorescence for the focuses of cancer in the early phase is much lower than that in the intermediate phase, and its spectral response is obscure. Fluorescence occurring in focus A of cancer and its peripheries B is magnified by image intensifier 3 shown in FIG. 1. Therefore, fluorescence peaked at both 630 nm and 690 nm from a hematoporphyrin derivative cannot easily be distinguished from that at 570 through 580 nm from the flesh not affected by cancer. Thus, cancer in the early phase cannot easily be detected.
In order to solve the aforementioned problem, the inventors of the present invention found that imaging of the spectral response should be synchronized with irradiation of the laser beam pulse used for a diagnosis so as to distinguish, as far as possible, fluorescence occurring from the flesh not affected by cancer from that occurring from the focuses of cancer. The inventors found that data for use in a precise diagnosis could be obtained by analyzing the image picked up by the aforementioned method.
The objective of the present invention is to present a cancer diagnosis device utilizing a laser beam pulse to facilitate detection of cancer in the early phase.
The other objective of the present invention is to present a cancer diagnosis device providing the capability to perform a spectrum analysis and also to observe the focuses of cancer without any interference to the spectrum analysis.